Altitude Compensation

[James Weiler]

On Wed, 11 Sep 1996, Markus Strobl wrote:

> > Does anyone do any altitude compensation?  Because, as altitude
> > increases, not only does the air mass density decrease, but the
> > percentage of oxygen decreases (simple physics - check books
> > before questioning or flaming) and the oxygen decrease is independent
> > of the density decrease.  
> 

Ford's EEC-IV system (speed density) utilizes a MAP sensor that also 
doubles as a Barometric sensor.  It switches to this other function at 
every start up and at wide open throttle.  I don't know when this type of 
sensor started to be used but I would guess early '80's and definitly up 
and including 1987.
The older EEC-III speed density systems used a separate Baro. sensor as well 
as a MAP.
cheers
jw